Dynamic QR Code requirement: QR must reflect remaining payable and may use UPI or authorized collector IDs for B2C invoices. Clarification prescribes that invoices to UIN holders are treated as B2C and require a Dynamic QR Code; UPI ID alone suffices (no bank/IFSC), third party collectors' UPI IDs may be used, foreign recipient invoices may omit QR, order IDs can substitute invoice numbers when uniquely linked, and QR amounts must show the remaining payable where part payments/adjustments exist, with full reconciliation on the invoice.